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EUKS AND MEIOSIS. "In summary, long-term asexuality is rare, and there is growing consensus that meiotic sex was present in the LECA and remains so in all major eukaryotic lineages." (LECA = last eukaryotic common ancestor), https://lnkd.in/deZ8DED View in LinkedIn

THE EXCEPTIONS. "On the other hand, very few examples can be found where genome sequencing has led us to infer a strictly asexual nature of the respective eukaryote." https://lnkd.in/deZ8DED View in LinkedIn

MAINSTREAM DOGMA. "From all of the prior observations we can safely conclude that meiotic sex in eukaryotes is the rule. It is very widespread, old, and clearly of major evolutionary importance." https://lnkd.in/deZ8DED View in LinkedIn

SINGLE EVENT. “Sexual reproduction is a nearly universal feature of eukaryotic organisms. Given its ubiquity and shared core features, sex is thought to have arisen once in the last common ancestor to all eukaryotes.” https://lnkd.in/ebVhXPf View in LinkedIn

SO ENDS this first of two weekends on the gene life cycle. This is at the heart of Darwinian evolution, although even the idea of genes was unknown to Darwin. New genetic material is the engine of diversity and fitness. Nature has found numerous inventive ways to freshen its genetic information content, in order to provide the organism with new phenotypes with which to conquer new niches. And very often, the timeframes involved in new gene generation and fixation are considerable. View in LinkedIn

MEIOSIS GENE REPERTOIRE. “Thus, like a V8 engine missing one spark plug, or a dog with three legs, the engine or animal can run but it is not pretty.” http://cshperspectives.cshlp.org/content/6/3/a016154.full View in LinkedIn

MEIOSIS GENE. “The gene repertoire to complete meiosis is apparently more plastic than thought.” Spo11 ortholog. http://cshperspectives.cshlp.org/content/6/3/a016154.full View in LinkedIn

PARASEXUAL RECOMBINATION. “In the C. albicans parasexual cycle, a low level of chromosomal recombination is detected in addition to chromosome loss and assortment, and these recombination events require the function of the C. albicans Spo11 ortholog, a central player in meiosis.” https://lnkd.in/ebVhXPf View in LinkedIn

VARIANT PARASEXUAL. “We also know about an unusual parasexual cycle that is extant in the most common human fungal pathogen, Candida albicans. In this species, mating occurs between diploids when the mating-type locus is homozygous (a/a and α/α) and the cells switch to a specialized mating cell type called opaque.” https://lnkd.in/ebVhXPf View in LinkedIn

ASPERGILLUS PARASEXUAL CYCLES. “More rapidly growing variants readily arise from homozygous diploids, but not from the corresponding haploid “parent,” and they are then reduced to a haploid state. The faster growing variants prove to harbor multiple recessive alleles, reciprocally epistatic, that together are beneficial but individually are deleterious, and thus they can only accumulate in the diploid and then be released during parasexual genome reduction. These studies illustrate the capacity of haploid-diploid-haploid parasexual cycles to generate genotypic and phenotypic diversity de novo.” http://cshperspectives.cshlp.org/content/6/3/a016154.full View in LinkedIn